Stolen and counterfeit replacement parts, particularly for automobiles, cost legitimate manufacturers billions of dollars in lost sales each year. Counterfeit and stolen articles can be extremely difficult to identify. The ability to track the ownership or verify the authenticity of an article throughout the distribution chain has become more important than ever.
Simple printed labels containing an identifier can be easily counterfeited. Manufacturing products with embossed or permanently formed identifiers can be extremely expensive.
U.S. Pat. Nos. 4,987,287 and 5,151,572 issued to Jack disclose use of a laser light beam to selectively cut or vaporize the adhesive and the label stock to form a stencil template containing an identifier. The adhesive contains an etchant or UV fluorescent dye. The etchant etches the substrate or the fluorescent dye diffuses into the substrate, leaving a negative fluorescent dye footprint of the identifier on a substrate. Using of a laser beam to cut a stencil, however, may weaken the label stock. Additionally, the required laser equipment may be cost prohibitive for some applications and is not particularly convenient for most users.
German Patent No. DE 38 13 303 discloses a self adhesive label and printing process in which an ink that contains a non-volatile thinner is printed onto carrier foil. The carrier foil containing the ink is adhered to the self adhesive label. The ink is absorbed from the carrier foil by the adhesive. When the self adhesive label is placed on a substrate, the non volatile thinner diffuses over time into the surface of the substrate, leaving traces in the substrate.